HDU 1159 LCS最长公共子序列

#include <cstdio>
#include <cstring>

using namespace std;
const int N = 1005;
#define max(a,b) a>b?a:b

char a[N] , b[N];
int dp[N][N];

int main()
{
    while(scanf("%s%s" , a+1 , b+1) != EOF){
        int l1 = strlen(a+1);
        int l2 = strlen(b+1);
        for(int i = 1 ; i<=l1 ; i++)
            for(int j = 1 ; j<=l2 ; j++){
                if(a[i] == b[j]) dp[i][j] = dp[i-1][j-1]+1;
                else dp[i][j] = max(dp[i-1][j] , dp[i][j-1]);
            }
        printf("%d\n" , dp[l1][l2]);
    }
    return 0;
}